Scaffolds Loaded with Dialdehyde Chitosan and Collagen-Their Physico-Chemical Properties and Biological Assessment.

In this work, dialdehyde chitosan (DAC) and collagen (Coll) scaffolds have been prepared and their physico-chemical properties have been evaluated. Their structural properties were studied by Fourier Transform Infrared Spectroscopy with Attenuated Internal Reflection (FTIR-ATR) accompanied by evaluation of thermal stability, porosity, density, moisture content and microstructure by Scanning Electron Microscopy-SEM. Additionally, cutaneous assessment using human epidermal keratinocytes (NHEK), dermal fibroblasts (NHDF) and melanoma cells (A375 and G-361) was performed. Based on thermal studies, two regions in DTG curves could be distinguished in each type of scaffold, what can be assigned to the elimination of water and the polymeric structure degradation of the materials components. The type of scaffold had no major effect on the porosity of the materials, but the water content of the materials decreased with increasing dialdehyde chitosan content in subjected matrices. Briefly, a drop in proliferation was noticed for scaffolds containing 20DAC/80Coll compared to matrices with collagen alone. Furthermore, increased content of DAC (50DAC/50Coll) either significantly induced the proliferation rate or maintains its ratio compared to the control matrix. This delivery is a promising technique for additional explorations targeting therapies in regenerative dermatology. The using of dialdehyde chitosan as one of the main scaffolds components is the novelty in terms of bioengineering.

Assessment of Melatonin-Cultured Collagen/Chitosan Scaffolds Cross-Linked by a Glyoxal Solution as Biomaterials for Wound Healing.

Chitosan (CTS) and collagen (Coll) are natural biomaterials that have been extensively used in tissue engineering or wound healing applications, either separately or as composite materials. Most methods to fabricate CTS/Coll matrices employ chemical crosslinking to obtain solid and stable scaffolds with the necessary porosity and mechanical properties to facilitate regeneration. In this study, we comparatively assessed the physicochemical properties of 3D scaffolds loaded with a cross-linker, glyoxal. Using a scanning electron microscope, we evaluated the microstructure of resultant matrices and their mechanistic testing by the determination of the compressive modulus (Emod), the maximum force (Fmax), thermogravimetric analysis (TG), Fourier Transform Infrared Spectroscopy-Attenuated Total Reflectance (FTIR-ATR), and proliferation rate in vitro using human epidermal keratinocytes and dermal fibroblasts cultured in presence of melatonin solution (10-5 M). We observed that enhanced content of collagen (50CTS/50Coll or 20CTS/80Coll compared to 80CTS/20Coll) significantly elevated the physicochemical capacities of resultant materials. Besides, presence of 5% glyoxal increased porosity, Emod and Fmax, compared to scaffolds without glyoxal. Finally, keratinocytes and dermal fibroblasts cultured on subjected matrices in presence of melatonin revealed a prominently enhanced growth rate. This indicates that the combination of glyoxal and melatonin make it imperative to consider these materials as a promising approach for targeting skin tissue engineering or regenerative dermatology.